The present invention relates to a process for welding or securing together two members, at least one of which is permeable to ultraviolet radiation to which it is exposed and in particular sheets made from glass and plastics material.
In numerous industrial constructions, transparent devices having a laminated structure are used, which offer a high resistance to thermal, mechanical and other shocks. Such devices comprise two transparent sheets, which are joined by means of a glue. One surface of one of the sheets is covered with a product containing a solvent and then the other sheet is applied. By eliminating the solvent through evaporation, appropriate heating permits the hardening or setting of the product. One type of product which is more particularly used is a solution composed of polyvinylbutyral, a plasticizer (such as diethyl-triglycol acetate in a proportion of 30%) and a solvent (such as an aliphatic alcohol or an ester). Such a composition is more particularly used in laminated glass windshields in which two sheets of glass having the desired shape are joined together by such a glue and in certain shields and casings in which a glass sheet and a plastic sheet are joined together. Gluing processes using this type of glue require an energy source that provide heating for a relatively long period of time. Furthermore, it is difficult for hardening to be perfect over the entire surface area of the support and traces of solvent can be left behind, which is detrimental to the strength, because the glue is not sufficiently hardened. In the case where plastic sheets are used, these solvent residues attack the plastic and the strength thereof is then further reduced.